114 lines
2.5 KiB
C
114 lines
2.5 KiB
C
#include "lib.h"
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#define DBG 1
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#define RUN_PART1 1
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#define RUN_PART2 1
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#define RUN_TEST1 1
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#define RUN_TEST2 1
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#define TEST1_EXPECT 3
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#define TEST2_EXPECT 6
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static
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char input[] = {
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#embed "day1_input.txt"
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};
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static
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char test[] = {
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#embed "day1_test.txt"
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};
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static
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unsigned long do_part1(size_t src_len, const char src[src_len]) {
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const char *s = src;
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unsigned long count = 0;
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unsigned long pos = 1'000'000'000'050;
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while (s < &src[src_len]) {
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const char *ns = s + 1;
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unsigned r = grabnum(ns, &ns);
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if (*s == 'L') {
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pos -= r;
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} else {
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pos += r;
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}
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count += pos % 100 == 0;
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s = ns + 1;
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}
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return count;
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}
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static
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unsigned do_part2(size_t src_len, const char src[src_len]) {
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const char *s = src, *ns = s + 1;
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unsigned count = 0;
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unsigned pos = 50;
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for (;s < &src[src_len]; s = ns + 1, ns = s + 1) {
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unsigned r = grabnum(ns, &ns);
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if (*s == 'L') {
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if (pos == 0) pos = 100;
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unsigned to_zero = pos;
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if (r < to_zero) {
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pos -= r;
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} else {
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unsigned over = r - to_zero;
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unsigned rots = over / 100;
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unsigned adjust = over % 100;
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count += 1 + rots;
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pos = (100 - adjust) % 100;
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}
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} else {
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unsigned to_zero = 100 - pos;
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if (r < to_zero) {
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pos += r;
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} else {
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unsigned over = r - to_zero;
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unsigned rots = over / 100;
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unsigned adjust = over % 100;
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count += 1 + rots;
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pos = adjust;
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}
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}
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}
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return count;
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}
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void _start() {
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#if RUN_TEST1
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print("PART 1 TEST: ");
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if (unsigned long v = do_part1(countof(test), test); v != TEST1_EXPECT) {
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print("FAILED (got ");
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printd(v);
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print(", expected " xstr(TEST1_EXPECT) ")\n");
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} else {
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print("PASSED\n");
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}
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#endif
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#if RUN_PART1
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print("PART 1 RESULT: ");
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printd(do_part1(countof(input), input));
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print("\n");
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#endif
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#if RUN_TEST2
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print("PART 2 TEST: ");
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if (unsigned v = do_part2(countof(test), test); v != TEST2_EXPECT) {
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print("FAILED (got ");
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printd(v);
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print(", expected " xstr(TEST2_EXPECT) ")\n");
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} else {
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print("PASSED\n");
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}
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#endif
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#if RUN_PART2
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print("PART 2 RESULT: ");
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printd(do_part2(countof(input), input));
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print("\n");
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#endif
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syscall(SYS_exit_group, 0);
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}
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